Scientists Map a Brain Down to Its Cells

THURSDAY, June 20 (HealthDay News) -- An international team of scientists report they've assembled the first three-dimensional model of the human brain that maps its anatomy on a cellular level.

Previously, doctors had been able to locate areas in the brain using imaging technologies such as MRI and CT scans. But the new model, called BigBrain, will allow researchers to peer at the organ's structures in much greater detail, producing images that are about 50 times more finely grained than the resolution of the best available MRI brain atlases.

The research is published in the June 21 issue of the journal Science.

"Reference brains have become an important tool for neuroscience, and especially for human brain research," Science senior editor Dr. Peter Stern said during a Wednesday news conference on BigBrain. "For a better understanding of the structural organization of something as complex as the human central nervous system, we really need a much, much closer look."

To make the model, the scientists carefully sliced a human brain that had been dipped in wax. Each slice was about 20 micrometers thick, about the same width as the finest human hair.

Researchers stained the delicate tissue slices -- there were more than 7,400 altogether -- with special dye to highlight cells, and then scanned them. The digitized images were then cleaned up and reassembled with the help of a super computer that could process the large volumes of data required to store and integrate the pictures.

The brain was donated to the project by a 65-year-old woman. Little is known about her, researchers said, except that she was free of any neurological or psychiatric problems. The team hopes to repeat the process in a sample of brains so they can see differences between brains that are young and old, male and female.

The first BigBrain model is freely available for anyone who wants to use it.

"It is a common basis for scientific discussions because everybody can work with this brain model and speak about the same basic findings," said study author Dr. Karl Zilles, director of the Institute of Neuroscience and Medicine, Julich Aachen Research Center, in Germany.

Researchers said the images would help surgeons who need to precisely place electrical probes when they need to stimulate brain tissue to treat disease.

"When patients, for instance, with Parkinson's are getting electrodes to decrease their tremors, these electrodes are placed using atlases that are more or less 2-D schematic drawings, so it's a big problem to place electrodes into new positions because [the current] atlas does not allow them to do it," explained lead researcher Dr. Katrin Amunts, director of the Cecile and Oskar Vogt Institute for Brain Research at the Heinrich Heine University Dusseldorf, in Germany.

The maps could also help doctors understand what happens to the brain when different parts become diseased or injured.

Experts who were not involved in the work praised the effort.

Michael Hawrylycz, an investigator at the Allen Institute for Brain Science in Seattle, said the effort to collect and image the data was a "massive undertaking."

The dataset that contains the BigBrain is a terabyte in size, or about 1,000 gigabytes. That's enough room to store about 435,000 photos snapped with an iPhone camera.

And it's about 100,000 times larger than the volume of data used by MRI brain maps.

Researchers say they'd like to make the resolution of the BigBrain even better, but they'll need more advanced computers than are currently available to do it.

Experts said the BigBrain will be an important framework for efforts such as the BRAIN initiative that was recently announced by President Obama and the European counterpart, The Big Brain Project.

Those studies aim to map brain's connectivity and function, and the new model could help give both projects a common point of reference.

Other researchers said they weren't sure how useful the BigBrain would be, however.

"From what I've read, it looks like the difference between the iPhone 3 and the iPhone 5," said Donald Stein, director of The Brain Lab at Emory University in Atlanta. "People have been mapping the circuits of the brain since the turn of the 20th century," he noted.

"It's a much better, cleaner, nicer, maybe a little more detailed picture," Stein said. "This is really looking at structure from dead tissue. Brain dynamics are really much more complicated than that. This is just one part of the story."